means An innate, unlearned impulse or pattern of behavior that pushes a creature to act in a certain way without conscious reasoning.

from From Latin instinctus, meaning 'impulse' or 'instigation' — the past participle of instinguere, 'to incite or impel.' That verb breaks down into in- ('on, toward') plus stinguere ('to prick, goad'), the same prodding root that gives us 'distinguish' and 'extinguish.' So at its heart, instinct is the inner goad — the prick that gets you moving before your mind has weighed in.